Reactions of Alkoxy- and Aryloxyphthalazines

The hydrolysis of such ethers to tautomeric phthalazinones or extranuclear hydroxyphthalazines has been covered in Sections 11.1.1 and 11.2, respectively. Other reactions are illustrated by the following classihed examples. 

1-Methyl-4-phenoxyphthalazine (196) gave 4-methyl-1-phthalazinamine (197) [excess neat ACONH4, 155°C, 1 h 55%] ° analogs likewise. 

4-Dimethoxyphthalazine (198, R = OMe) gave 4-methoxy-1-phthalazinamine (199, R = NH2) (NaNH2, PhH, AcEt, reflux, 30 min 16% with 77% recovery of substrate) similar treatment of 1-methoxy-4-phenylphthalazine (198, R = Ph) gave 4-phenyl-1-phthalazinamine (199, R = Ph) (likewise 6% with 85% recovery of substrate).  

Note This thermal rearrangement of alkoxyphthalazines appears to occur under conditions that are relatively mild in comparison with those required in analogous systems. 

1-Butoxy-4-phenylphthalazine (200) gave 2-butyl-4-phenyl-l(277)-phthalazi-none (201) (BuOH, reflux, 2h %).  

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